Protecting film for protecting image and method for producing recorded material using the same

ABSTRACT

A protecting film for covering a recording face of a recording medium includes a support, a first protective layer formed of thermoplastic resin and formed on the support, and a second protective layer formed of thermoplastic resin, and laminated on the first protective layer. An image is formed on the recording face by a thermal transfer type overcoat process.

BACKGROUND OF THE INVENTION

The present invention relates to a film for protecting an image forprotecting an image formed by a recording system such as an ink jetsystem and a method for producing a recorded material using the same.

An ink jet system is a printing system to carry out printing bydischarging droplets of ink from a minute nozzle of a recording head toadhere the same to a recording face of a recording medium such as paper.Recently, a thermal transfer type overcoat system is known in which, byusing a film for protecting an image having a constitution of laminatinga thermoplastic resin layer on a support, the resin layer is heated andpressure bonded on the recorded face of a recording medium on which animage has been formed by an ink jet system, subsequently the support isdetached from the resin layer to provide a protective layer constitutedof the resin layer, in order to improve an image fastness and the like(for example, refer to JP-A-2000-233474).

Generally, in transferring and forming a protective layer by an overcoatsystem treatment (overcoat system treatment includes a detachingprocess-free system by using a film for protecting an image with anadhesive layer in addition to the thermal transfer type having adetaching process of a support) including the thermal transfer type, itis usual to employ a process allowing a thermoplastic resin layer totransfer thermally from a support to a recording medium by using aheating and pressure bonding apparatus. However, consideration of damageof a printed ink-accepting layer with heat and degradation of a recordedimage due to it gives no other choice of a limited temperature of heatand period of time that can be added by the heating and pressure bondingapparatus. Therefore, sometimes adhesiveness between a recording mediumand a thermoplastic resin layer (protective layer) is not sufficient inthe related method.

Further, in recent years, high speed ink absorption properties have beenrequired for an ink jet recording medium along with speed up of printingby an ink jet system and compositional ratio of a porous inorganicparticle such as amorphous silica to a binder in the ink-accepting layerthereof demonstrates an upward trend. However, surface of such theink-accepting layer forms irregularities to give poor smoothness andadhesiveness of a thermoplastic resin layer to the surface tends todecrease significantly. This is due to the fact that sufficient meltingand penetration of the thermoplastic resin layer into concave portionstends to occur difficultly.

As described above, a thermal transfer type overcoat system using arelated film for protecting an image is forced to carry out thermaltransfer in a mild heating condition that does not induce degradation ofa recorded image by heat. Therefore, adhesiveness of a thermoplasticresin layer to a recording medium, especially to an ink jet recordingmedium having an ink-accepting layer containing a porous inorganicparticle is quite inadequate, resulting in such a problem that a part ofthe resin layer is lifted from the recorded face or, in a worse case, isdetached with a support during a process for detaching a support(decrease in detachability of a support). The lift of a resin layer fromthe recorded face becomes especially problematic when an image is formedby using a pigment ink. That is, when a pigment ink is driven into arecording face, most of coloring material (pigment) do not penetrateinto a recording medium and attach to the recording face. Therefore, thelift of the resin layer induces decreasing in a image density ortransferring the coloring material to the lifted resin layer side,resulting in generation of bleeding or stripping of the image.

Therefore, as a technique for achieving an excellent adhesiveness with arelatively mild heating condition that does not generate degradation ofa recorded image with heat, there may be a method to lower the glasstransition temperature (Tg) of a resin constituting a thermoplasticresin layer in a film for protecting an image. However, when the glasstransition temperature Tg of a thermoplastic resin layer to become aprotective layer by being transferred to a recording medium is loweredto an extent that can achieve the purpose, scratch resistance (abrasionresistance) of the thermoplastic resin layer decreases to generate sucha problem that surface of the protective layer tends to be suffered byscratches and the like. In addition, use of a thermoplastic resin havinga low glass transition temperature Tg makes the surface of theprotective layer sticky at ordinary temperature to generate anotherproblem of decrease in blocking resistance.

SUMMARY OF THE INVENTION

Accordingly, the purpose of the invention is to provide a film forprotecting an image capable of allowing a thermoplastic resin layer toadhere to a recorded face of a recording medium under a relatively mildheating condition that does not induce degradation of the image, ofdetaching smoothly, in a subsequent detaching process of a support, onlythe support without lifting or stripping the resin layer from therecorded face, and of providing a high grade recording medium excellentin glossy feeling, scratch resistance, blocking resistance and the like;and to provide a method for producing a recorded material using thesame.

A protecting film for covering a recording face of a recording medium,an image being formed on the recording face by a thermal transfer typeovercoat process, the protecting film comprising:

-   -   a support;    -   a first protective layer, formed of thermoplastic resin, and        formed on the support; and    -   a second protective layer, formed of thermoplastic resin, and        formed on the first protective layer.

Preferably, the thermoplastic resin forming the first protective layerhas a glass transition temperature higher than that of the thermoplasticresin forming the second protective layer.

Here, it is preferably that, a difference between the glass transitiontemperature of the thermoplastic resin forming the first protectivelayer and the glass transition temperature of the thermoplastic resinforming the second protective layer is from 10 to 100° C.

Here, it is preferably that, the glass transition temperature of thethermoplastic resin forming the first protective layer is from 30 to130° C.

Preferably, the first protective layer includes an inorganic particle.

Here, it is preferably that, a content of the inorganic particle is from10 to 60% by weight relative to resin solid content.

Here, it is preferably that, the inorganic particle is colloidal silica.

Here, it is preferably that, the first protective layer includes acontinuous phase formed of thermoplastic resin and a dispersed phaseformed of thermoplastic resin dispersed in the continuous phase. Thecontinuous phase contains the inorganic particle.

Preferably, a complex elastic modulus of the thermoplastic resin formingthe second protective layer is 4.0×10⁸ Pa or more at 40° C. in atemperature dispersion curve of dynamic viscoelasticity that is measuredat frequency of 1 Hz, temperature rise rate of 2° C./min and minimumtension of 10 mN.

Preferably, a complex elastic modulus of the thermoplastic resin formingthe second protective layer is 2.5×10⁵ Pa or less at 100° C. in atemperature dispersion curve of dynamic viscoelasticity that is measuredat frequency of 1 Hz, temperature rise rate of 2° C./min and minimumtension of 10 mN.

Here, it is preferably that, the glass transition temperature of thethermoplastic resin forming the second protective layer is from −20 to60° C.

Preferably, the first protective layer includes wax.

According to the present invention, there is also provided a method forproducing a recorded material by using a protecting film, comprising thesteps of:

-   -   forming an image on a recording face of a recording medium;    -   laminating the recording medium on which the image is formed and        the protecting film so that the recording face is superposed on        the second protective layer of the protecting film;    -   applying heat and pressure to the laminated recording medium and        protecting film so as to bond the recording medium and        protecting film each other,    -   wherein heating temperature at the heating and pressure bonding        is equal to or greater than the glass transition temperature of        the thermoplastic resin forming the second protective layer.

Preferably, the image is formed by an ink jet system.

According to the present invention, there is also provided a recordedmaterial produced by the method for producing the recorded material.

The film for protecting an image according to the invention is intendedto have a protective layer (thermoplastic resin layer) of two-layerconstitution including a layer to be a surface protective layer of animaged surface and a layer to be an adhesive layer to the imaged face,and to provide each of the layers with excellent propertiescorresponding to the role thereof. Therefore, the film making itpossible to carry out smoothly thermal transfer processing and to givegood protective properties for the imaged face. In other words, the filmfor protecting an image according to the invention can give, at heatingand pressure bonding to a recording medium, a good adhesiveness betweenthe protective layer (thermoplastic resin layer) and a recorded facewith a low smoothness in addition to a smooth recorded face, needless tosay, under a relatively mild condition such as not inducing degradationof a recorded image. On the other hand, at detaching the support, thesupport can be detached smoothly and finely without generating lift andthe like of the thermoplastic resin layer from the recorded face. As theresult, a high grade recorded material having a protective layer can beprovided, which has no disarray of an image, no interfusion of an airbubble between the protective layer and the recorded face, and also ishighly colored, excellent in scratch resistance and blocking resistance.Further, the film for protecting an image according to the invention canbe left to stand in a state of being stacked or wound into a roll for along period of time without generating blocking easily to give anexcellent storability.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent by describing in detail preferred exemplary embodimentsthereof with reference to the accompanying drawings, wherein:

FIG. 1 is a view explaining diagrammatically a cross-section of anembodiment of the film for protecting an image according to theinvention; and

FIG. 2 is a side view showing schematically an embodiment of aproduction apparatus for use in practicing the production methodaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, first, the film for protecting an image (hereinafter, alsoreferred to as “protective film” simply) according to the invention willbe described in detail.

FIG. 1 is a view explaining diagrammatically a cross-section of oneembodiment of the protective film according to the invention. Aprotective film S includes a support Bs and a thermoplastic resin layerCs. The thermoplastic resin layer Cs has a first protective layer Cs1and a second protective layer Cs2 sequentially laminated on the supportBs. The first protective layer Cs1 and the second protective layer Cs2are thermally transferred from the support Bs to a recorded face of arecording medium while maintaining the laminated state to become aprotective layer covering the recorded face so that the first protectivelayer Cs1 becomes the outermost layer of the protective layer. On theother hand, the support Bs is detached from the first protective layerCs1 in the thermal transfer process and recovered.

As to the support for use in the invention, one, which is provided withheat resistance and mechanical strength capable of maintaining stablythe figure under a predetermined heating and pressure bonding conditionat overcoating and good detachability from the thermoplastic resin layerheated and pressure bonded to the recorded face, is used. Examples ofthe usable support include a sheet or film made of such material aspolyethylene terephthalate (PET), biaxially oriented polypropylene(OPP), polyethylene naphthalate (PEN), polyphenyl sulfide (PPS),polyether sulfone (PES), polystyrene (PS) or polypropylene (PP).

As to thickness of the support; it is only required to set so as to givethe functions and not limited in particular. However, in considerationof thermal conductivity, adhesiveness, handleability and inhibiting airbubble interfusion at overcoating, it is preferably from 8 to 60 μm,more preferably from 10 to 50 μm.

In order to improve heat resistance further, according to need, thesupport may also be incorporated with a ceramic fine particle, or coatedon the surface thereof with a heat-resistant resin such aspolyester-based resin, polyacrylic ester-based resin, polyvinylacetate-based resin, polyurethane-based resin, styrene-acrylate-basedresin, polyacrylate-based resin, polyacrylamide-based resin,polyamide-based resin, polyether-based resin, polystyrene-based resin,polyethylene-based resin, polypropylene-based resin, polyolefin-basedresin, vinyl-series resin such as polyvinyl chloride resin or polyvinylalcohol resin, cellulose-series resin such as cellulose resin,hydroxyethyl cellulose resin or cellulose acetate resin, polyvinylacetal-series resin such as polyvinyl acetoacetal or polyvinyl butyral,silicone-modified resin or long-chain alkyl-modified resin.

Further, for the purpose of improving detachability, inhibitingattachment of dust due to a static charge, improving blockingresistance, improving design properties of the surface of the protectivelayer (thermoplastic resin layer) and the like, the protective layerforming surface and/or the reverse side surface of the support may alsobe subjected to various surface treatments such as detaching (release)treatment, antistatic treatment, corona discharge treatment and embosstreatment. The release treatment is a treatment of coating a surface tobe treated with silicone resin, fluorocarbon-based resin, melamine-basedresin, colloidal silica or the like as a release agent. The treatmentprovided on the protective layer-forming surface is effective forimproving detachability (transferability) of the support, and thetreatment provided on the surface reverse to the protectivelayer-forming surface is effective for inhibiting thermal adhesion to aheating and pressure bonding unit such as a heat roll, improvingblocking resistance, bettering sliding properties during paper feeding,and the like. Thickness of the releasing layer is usually around 0.1 to5 μm. The corona discharge treatment is a treatment in which a support(film) is run thorough a space where corona discharge exists (forexample, a gap between a pair of opposing electrodes) to improve wettension of the surface. Operating the treatment to this protectivelayer-forming surface can enhance adhesiveness between the support andthe protective layer.

Specific preferable examples of the support include an OPP film havingbeen subjected to a corona discharge treatment to the protectivelayer-forming face and a PET film having been subjected to a releasetreatment to the surface reverse to the protective-layer forming surface(non-protective layer-forming surface). An OPP film is excellent inblocking resistance, however, it is poor in adhesiveness to theprotective layer when used as a support without modification and such atrouble may generate that the protective layer is detached from thesupport before a thermal transfer processing. Operation of a coronadischarge treatment to the protective layer-forming surface, however,can resolve such a defect of OPP film to give a protective film takingadvantage of characteristics of OPP film. In contrast to OPP film, PETfilm has such a trouble that it is poor in blocking resistance,therefore preference is given to one having been subjected to a releasetreatment to a non-protective layer-forming surface as described above.

On the other hand, the thermoplastic resin layer that is laminated onthe support is constituted of a first protective layer and a secondprotective layer that are thermoplastic resin layers independent of eachother having different compositions, respectively. Constitution of thethermoplastic resin layer includes two conformations such as a firstconformation and a second conformation as described below.

[First Conformation]

The first conformation is a conformation in which a thermoplastic resinforming the first protective layer has a glass transition temperature(Tg) higher than that of a thermoplastic resin forming the secondprotective layer. As described above, two-layer construction of thethermoplastic resin layer and selection of the thermoplastic resin forforming the second protective layer, which is pressure bonded to arecorded face, to have a glass transition temperature Tg lower than thatof the first protective layer make it possible to assure a goodadhesiveness (good detachability of the support) to the recorded facebecause of the second protective layer, as well as to form a protectivelayer that is excellent in scratch resistance (abrasion resistance) andblocking resistance and hardly damaged with a scratch because of thefirst protective layer.

The aforesaid “glass transition temperature Tg of a thermoplastic resinforming the first protective layer or the second protective layer” meansa weight average glass transition temperature Tg. That is, for example,when the first protective layer contains two kinds of thermoplasticresins having a glass transition temperature Tg of 77° C. and a glasstransition temperature Tg of 50° C. respectively by a weight ratio of3:2, the weigh average glass transition temperature Tg of thethermoplastic resin forming the first protective layer is[(77×3+50×2)/(3+2)]=66.2° C., the 66.2° C. being “the glass transitiontemperature Tg of the thermoplastic resin forming the first protectivelayer.” And in this case, the Tg (weight average glass transitiontemperature Tg) of a thermoplastic resin forming the second protectivelayer is lower than 66.2° C.

Preferably difference between the glass transition temperature Tg of athermoplastic resin forming the first protective layer and the glasstransition temperature Tg of a thermoplastic resin forming the secondprotective layer is from 10 to 100° C., more preferably from 20 to 90°C.

The absolute value of the glass transition temperature Tg of athermoplastic resin forming the first protective layer is, from aviewpoint of balance between scratch resistance and blocking resistance,preferably from 30 to 130° C., more preferably from 35 to 125° C.

On the other hand, the absolute value of the glass transitiontemperature Tg of a thermoplastic resin forming the second protectivelayer is, from a viewpoint of adhesiveness and film-forming properties,preferably from −20 to 60° C., more preferably from −15 to 55° C.

[Second Conformation]

The second conformation is a conformation in which the first protectivelayer contains an inorganic particle. The second conformation isintended to improve blocking resistance and scratch resistance byincorporating an inorganic particle in the first protective layer tobecome the outermost protective layer, resulting in giving the sameeffect as the thermoplastic resin layer in the first conformation.Incorporation of an inorganic particle to the second protective layer isnot required particularly from a point of improving blocking resistanceand the like, but incorporation of an inorganic particle to the secondprotective layer is possible according to need. In that case, content ofthe inorganic particle in the second protective layer is preferably lessthan that of the inorganic particle in the first protective layer.

Preference is given to colloidal silica as the inorganic particle.Content of the inorganic particle is preferably 10 to 60% by weightrelative to resin solid content of the first protective layer. A contentof the inorganic particle outside of the range may makes it difficult tobring a balance between film-forming properties, blocking resistance andcolor-forming properties.

In the second conformation, in addition to contain an inorganicparticle, the first protective layer is preferably constituted of acontinuous phase formed of a thermoplastic resin and a dispersed phaseconstituted of a thermoplastic resin dispersed in the continuous phase.In the constitution, the inorganic particle is contained in thecontinuous phase. Thus, by constituting the first protective layer witha continuous phase and a dispersed phase consisting mainly ofthermoplastic resin, and further incorporating an inorganic particle inthe continuous phase, when a recorded material covered with a protectivelayer is stored by being housed in a commercially available album or aclear file, it is possible to prevent effectively such troubles thatsurface of the protective layer of the recorded material sticks stronglyto a cover film that is overlaid on the surface of a substance placed inthe album, and that surface shape of the protective layer alters togenerate change in gloss.

As for a thermoplastic resin forming the continuous phase, preference isgiven to a thermoplastic resin that can exert good film-formingproperties at a temperature lower than that of a thermoplastic resinforming the dispersed phase, and has a glass transition temperature Tgin a range of from −50 to 60° C.

On the other hand, the dispersed phase is preferably formed with athermoplastic resin having a glass transition temperature Tg of 60° C.or more. As for MFT, 100° C. or more is preferable.

Percentage of the dispersed phase in the first protective layer ispreferably determined to 10 to 60% by weight relative to resin solidcontent in the first protective layer. A percentage of the dispersedphase less than 10% by weight may not prevent effectively aforementionedtroubles in the case of placing a recorded material covered with theprotective layer in an album or the like, and a percentage more than 60%by weight may harm film-forming properties of the continuous phase.

Further, in the second conformation, from a view point of assuring goodadhesiveness to a recorded face and good detachability of the support, athermoplastic resin forming the second protective layer has preferably aTg of −20 to 60° C., more preferably −15 to 55° C.

Here, in the second conformation, there is no such restriction for athermoplastic resin forming the first protective layer and the secondprotective layer as that existing in the first conformation. Athermoplastic resin forming the first protective layer may have a lowerglass transition temperature Tg compared with a thermoplastic resinforming the second protective layer, or thermoplastic resins forming thefirst protective layer and the second protective layer, respectively,may have the same glass transition temperatures (Tgs). Of course, aconformation combining the first and second conformations, that is, aconformation in which a thermoplastic resin forming the first protectivelayer has a glass transition temperature Tg higher than that of athermoplastic resin forming the second protective layer and the firstprotective layer contains an inorganic particle, is also encompassed inthe invention.

The protective film according to the invention comprising thethermoplastic resin layer having such the constitution as the first orsecond conformation is, usually, stored in stacking many films in a cutsheet, or winding a long sheet of the film in a roll. In both storingshapes, blocking between the second protective layers or the secondprotective layer and the support is comprehended. Therefore, from aviewpoint of inhibiting such blocking at film storage, a thermoplasticresin whose complex elastic modulus at 40° C. obtained by a dynamicviscoelasticity measurement is 4.0×108 Pa or more is preferable, and5.5×108 Pa or more is more preferable as a thermoplastic resin to be asecond protective layer-forming material. Use of a thermoplastic resinhaving a complex elastic modulus within the range makes it unnecessaryto conduct a special treatment for preventing blocking that was carriedout conventionally, for example a release treatment of the supportsurface, to enhance productivity of the protective film.

On the other hand, interfusion of air bubbles between a protective layerand a recorded face makes appearance very ugly, and the air bubbleexisting on an image leads to decrease in image density. Therefore, froma viewpoint of inhibiting such interfusion of the air bubble, the secondprotective layer is formed preferably of a thermoplastic resin whosecomplex elastic modulus at 100° C. obtained by a dynamic viscoelasticitymeasurement is in a range of 2.5×105 Pa or less preferably, and 2.0×105Pa or less more preferably.

Use of a thermoplastic resin satisfying the two ranges of complexelastic modulus (at 40° C. and 100° C.) as a second protectivelayer-forming material can enhance blocking resistance during filmstorage and air bubble interfusion inhibition properties at the sametime.

In this connection, “the complex elastic modulus” in the invention isobtained as a complex elastic modulus at 40 or 100° C. of a temperaturedispersion curve formed by measuring dynamic viscoelasticity using aviscoelasticity spectrometer at a temperature of 21±2° C. and a humidityof 60±5%, under nitrogen gas flow, at a frequency of 1 Hz, a temperaturerise rate of 2° C./min and a minimum tension of 10 mN.

In the first and second conformations, examples of thermoplastic resinsto be the first or second protective layer-forming material includepolyvinyl acetal, acrylic resin, acrylic-styrene resin, acrylic-urethaneresin, vinyl chloride vinyl acetate-based resin and styrene-based resin.One kind or a mixture of two or more kinds of these resins are used toadjust such characteristic values as the glass transition temperature Tgand complex elastic modulus to fall in the range.

Figure of the thermoplastic resin is not particularly limited, and asolid figure such as a pellet or an emulsion may be usable. Preferenceis given to using an aqueous resin emulsion formed by dispersing athermoplastic resin particle in an aqueous liquid containing water asthe principal solvent, the average particle diameter of thethermoplastic resin particle being around from 50 to 300 μm, from aviewpoint of film-forming properties and the like.

Especially, among the aqueous resin emulsions, a core-shell type resinemulsion containing a thermoplastic resin particle of a core-shellstructure as a dispersoid exerts an excellent film-forming properties,and is effective as a material for forming the first and secondprotective layers, above all, for forming the first protective layer tobe the outermost layer. The core-shell structure is a structure in whichdifferent two or more kinds of resins exist in phase separation and,usually, consisting of a core portion and a shell portion enclosing thecore portion. The core-shell structure includes such figures that theshell portion covers the core portion completely, the shell portioncovers a part of the core portion, a part of a resin constituting theshell portion forms a domain or the like in the core portion, and amultilayer having at least one resin layer, between the core portion andthe shell portion, with a composition different from that of these. Allthe figures can be used suitably in the invention.

For the thermoplastic resin particle of the core-shell structure, theweight average glass transition temperature Tg of a thermoplastic resinconstituting the core portion is preferably higher than the weightaverage Tg of a thermoplastic resin constituting the shell portion. Morepreferably, difference between the weight average glass transitiontemperatures (Tg) of both resins is 30° C. or more. Thus, a largerweight average glass transition temperature Tg of a thermoplastic resinconstituting the core portion makes it possible to satisfy both offilm-forming properties and blocking resistance.

The core-shell type resin emulsion can be produced by a publicly knownseed emulsion polymerization method. As for a resin constituting thecore portion or the shell portion, the thermoplastic resin can bepreferably used. Adjustment of the glass transition temperature Tg ofthe core portion and shell portion can be carried out by controllingsuitably kind of monomers or the like.

Further, a film-forming auxiliary agent may also be incorporated to theaqueous resin emulsion to enhance film-forming properties, allowing toform a clear protective layer without a crack and the like. Especially,as for an aqueous resin emulsion for the first protective layer to bethe outermost protective layer, preference is given to using an emulsioncontaining a film-forming auxiliary agent. As for the film-formingauxiliary agent, one that can control the minimum film formationtemperature of the aqueous resin emulsion may be usable. For example,butylcellosolve, butylcarbitol, butylcellosolve acetate, butylcarbitolacetate, diethylene glycol, hexanol, 2-ethyl hexanol, Texanol and thelike can be mentioned. One kind solely or a mixture of two or more kindsof these can be used. Content of the film-forming auxiliary agent ispreferably from 1 to 20% by weight, more preferably from 3 to 15% byweight relative to the resin solid content:

In order to improve further scratch resistance and blocking resistance,the first protective layer is preferably incorporated with wax. Examplesof wax include paraffin wax (hydrocarbon of carbon number 20 to 40),microcrystalline wax (hydrocarbon of carbon number 30 to 60), carnaubawax (ester of fatty acid of carbon number 24 to 32 and alcohol),candelila wax (fatty acid of carbon number 32, 30 and alcohol and esterthereof), rice wax (ester of fatty acid of carbon number 16 to 32 andalcohol), Japanese wax (ester with glycerin containing also dibasic acidof carbon number 16 to 22), bees wax (ester of fatty acid of carbonnumber 16 to 32 and alcohol and hydrocarbon), whale wax (ester of fattyacid of carbon number 16 and alcohol), montan wax (ester of fatty acidof carbon number 20 to 32 and alcohol and resin base), ozokerite(hydrocarbon), ceresin (whitely purified ozokerite), polyethylene wax,Fischer tropush wax (hydrocarbon of carbon number 17 to 78), amide wax(fatty acid amide or bisamide), hardened caster oil (castor wax, esterof 12-hydroxy stearic acid and glycerin), synthetic wax containing esterof monovalent alcohol and fatty acid as the principal component, Gerbewax (ester) obtained from reaction of branched higher alcohol and fattyacid through Gerbe reaction and the like. One kind or a combination oftwo or more kinds of these can be used. Examples of the suitablecommercially available wax include Nopco 1245-M-SN and Nopcoat PEM-17from SAN NOPCO Limited, Chemipearl series WF-640, W-700, W-200 fromMitsui Chemicals, Inc. and the like. Content of the wax is preferablyfrom 1 to 10% by weight, more preferably from 2 to 9% by weight relativeto the resin solid content.

To the first and second protective layers, according to need, variousadditives such as a ultraviolet absorber, a light stabilizer, anoxidation inhibitor, a water resistant agent, an antiseptic agent, asurfactant, a thickener, a flow improver, a pH adjuster, a levelingagent and an antistatic agent may also be added. These additives can beadded to either one of the two layers or to both of them.

The total thickness of the thermoplastic resin layers (first and secondprotective layers) is preferably 2 to 50 μm, in particular from 3 to 30μm, and above all 5 to 30 μm. A thickness of less than 2 μm might notgive a sufficient image protection effect, and that more than 50 μmmight decrease transparency. The thickness of respective layers may beadjusted suitably to make the total thickness of the thermoplastic resinlayers fall in the range while considering degree of irregularities ofthe recorded face and image quality (translucent feeling, glossy feelingand the like). Although not restricted particularly, preferably thethickness of the first protective layer is from 1 to 28 μm, and that ofthe second protective layer is from 2 to 29 μm.

When producing the protective film S as shown in FIG. 1, first, each ofcoating liquids (aqueous resin emulsion) for the first protective layerCs1 and the second protective layer Cs2 is prepared. Then, on thesupport Bs having been subjected arbitrarily to necessary treatmentssuch as a release treatment, the coating liquid for the first protectivelayer Cs1 is coated and dried and, subsequently, the coating liquid forthe second protective layer Cs2 is coated and dried to produce theprotective film S. Coating of the coating liquid can be carried out withvarious coating methods such as a roll coating method, a rod bar coatingmethod or an air knife coating method.

Next, the production method for the recorded material according to theinvention employing the film for protecting an image will be describedon the basis of a preferable embodiment employing the protective film Sas shown in FIG. 1.

The method for producing a recorded material (hereinafter, also referredto as “production method” simply) according to the embodiment comprisesan image formation process for forming an image by driving an ink to arecording face of a recording medium with an ink jet system, and anovercoating process including heating and pressure bonding theprotective film S to the recording face having been formed of the imagevia a thermoplastic resin layer Cs and, subsequently, detaching thesupport Bs.

The recording medium for use in the production method according to theinvention is only required to be capable of a ink jet recording andincludes, for example, high-quality paper, recycled paper, copyingpaper, bond paper, ink jet recording paper, art paper, coated paper,cast-coated paper, resin-coated paper, baryta-coated paper, board paper,Japan paper, nonwoven cloth; resin films made of polyethylene,polypropylene polystyrene, polyethylene terephthalate and the like. Inparticular, the ink jet recording paper is most appropriate andpreferable for a ink jet recording because, combined with the protectivelayer according to the invention, it allows to make a recorded materialof a high image quality and high grade and a high storability comparablewith silver halide photography. The protective film according to theinvention can form a protective layer excellent in adhesiveness even tothe surface of the ink jet recording paper that is poor, usually, insurface smoothness.

The ink jet recording paper has a constitution of providing anink-accepting layer containing an inorganic particle on a base material.Examples of the base material include plastic film made of polyethylene,polypropylene, polyethylene terephthalate and the like, and sheet madeof paper material such as bond paper, coated paper and laminated paper.

As the inorganic particle, for example, a porous inorganic particle suchas porous amorphous silica, porous amorphous alumina or porous amorphousmagnesium carbonate is used preferably. Content of the inorganicparticle is preferably 30 to 90% by weight in terms of a solid contentin the ink-accepting layer.

In the ink-accepting layer, a water-soluble polymer such as polyvinylalcohol, vinyl acetate or acrylic, or an emulsion is contained as abinder for the inorganic particle. Content of the binder is preferably 5to 60 weight parts relative to 100 weight parts of the porous inorganicparticle. Further, the ink-accepting layer may be incorporated with onekind or two or more kinds of various additives such as a dye-fixingagent, fluorescent brightener, fungicide, antiseptic agent, surfactant,thickener, pH adjuster, antifoaming agent, hardening agent, levelingagent and ultraviolet absorber according to need.

The ink-accepting layer may be formed by coating a coating liquidcontaining an inorganic particle, binder and the like on a base materialwith various methods such as a roll coating method, a rod bar coatingmethod or an air knife coating method. The thickness of theink-accepting layer in this case is preferably from 10 to 60 μm from aviewpoint of ink absorption properties and prevention of powder fallingand the like. Further, material feeling, feeling and the like of theink-accepting layer are not particularly restricted and may be ofmat-tone, high-glossy tone such as being subjected tomirror-gloss-finishing by a casting method or semi-glossy tone.

The ink for use in the production method according to the invention isonly required to be an ink for an ink jet recording, and either a dyeink or a pigment ink may be usable. An ink for an ink jet recording isgenerally formed by adding a colorant such as dye or pigment to water,and is usually incorporated further with various organic solvents orsurfactant in order to retain humidity, adjust penetration, or the like.In particular, a pigment ink excels in light stability, water resistanceand the like compared with a dye ink to allow a recorded materialexcelling in long term storability to be formed by an synergistic effectof the protective film according to the invention, and is preferable.When forming a colored image, three inks of elementary colors ofsubtractive color mixing, that is, yellow, magenta and cyan, or inks offour or more colors including additionally black and other colored inksare used.

FIG. 2 is a side view showing schematically a substantial part of aproduction apparatus for use in practicing the production method. Theproduction apparatus 10 has such a constitution that a thermal-transfermechanism is mounted following a recording head of an ink jet printerbeing compatible with a roll paper, and is provided with an ink jetrecording section 1 used in the image formation process and anovercoating section 2 used in the overcoating process. A cutter 3 isprovided near a paper ejection section to make it possible to eject acontinuous sheet (long sheet) after cutting it into a desired length.Constitution of respective sections of the production apparatus 10 issubstantially the same as that in a publicly known inkjet printer and athermal-transfer mechanism.

The ink jet recording section 1 is provided with a recording head 11that is scanned bi-directionally in the vertical direction to atransporting direction of a recording medium M to drive inks ofrespective colors from jet nozzle openings of a nozzle opening plane 11a to the recording face of the recording medium M in a state of beingwound in a roll on the basis of input image information. By repeatingtransporting of the recording medium M and bi-directional scanning ofthe recording head 11, a desired image is formed on the recording face.

The recording head 11 may employ either a continuous system in which anink is discharged continuously at certain time intervals and thedischarged ink droplet is deflected to complete an image, or anon-demand system in which an ink is discharged corresponding to imagedata. But, from a view point of capability of a fine drive control and alittle volume of waste fluid, an on-demand system is preferable. As foran ink discharge system, there are such systems that an ink isdischarged by using an electricity-machine converter such as apiezoelectric element, and that an ink is discharged by heating it withan electricity-heat converter such as a heat-generating element having aheat-generating resistive element. And the system is not restrictedparticularly in the invention.

The overcoating section 2 includes a supply member 21 for supplying theprotective film S on the recorded face of the recording medium M, aheating and pressure bonding member 22 for heating and pressure bondingthe thermoplastic resin layer Cs (first protective layer Cs1 and secondprotective layer Cs2) of the protective film S to the recording facehaving been formed of an image, and a detaching member 23 for detachingthe support Bs from the thermoplastic resin layer Cs having been heatedand pressure bonded.

The supply member 21 is provided with the protective film S, a supplyroll that winds the protective film S and constitutes a rotation centerduring film supply, a pressurizing roll for pressurizing the run outprotective film S onto the recording medium M, and the like.

The heating and pressure bonding member 22 is provided with a pair ofrolls housing a heater (heat roll). Distance between both rolls isintended to be settable and adjustable arbitrarily, making it possibleto conduct a heating and pressure bonding treatment for a sheet-likematerial running through between the pair of rolls. The heating andpressure bonding member is only required such that it can conduct aheating and pressure bonding treatment for a sheet-shaped material, andmay be a thermal head, a pressing iron, a commercially availablelaminator, and the like.

The detaching member 23 is provided with a pressing roll, a winding rollfor winding the support Bs, and the like.

At the overcoating section 2 having such the constitution, theovercoating process proceeds as follows. First, to the recording face ofthe recording medium M, on which an image has been formed by the ink jetrecording section 1, the protective film S is supplied by the supplymember 21 so that the recorded face and the second protective layer Cs2face with each other, and stacked to form a laminate.

Subsequently, the laminate is pressurized under heating (heating andpressure bonding treatment) by running through a nipping part betweenthe pair of rolls of the heating and pressure bonding member 22. Heatingtemperature at this time is determined such that it is higher than theglass transition temperature Tg of a thermoplastic resin forming thesecond protective layer Cs2. The heating temperature is lower comparedwith a heating temperature when an conventional protective film of asingle-layer structure is used.

Due to the heating and pressure bonding treatment, the resin of thesecond protective layer Cs2 contacting to the recorded face melts topartake fluidity and fits in irregularities of the recorded face toresult in exerting a sufficient adhesive force. Thus, the thermoplasticresin layer Cs is pressure bonded to the recorded face with a goodadhesiveness to form the protective layer C. On the other hand, sincethe heating condition (heating temperature, heating time) at the heatingand pressure bonding treatment is a mild one that does not lead todegradation of a recorded image, there is no possibility for leading toa disadvantage such as discoloration of the recorded image.Subsequently, when the temperature of the laminate falls off, thesupport Bs is detached by the detaching member 23. At this time, sincethe thermoplastic resin layer Cs (protective layer C) adheres tightly tothe recorded face, there is no lift or stripping of the thermoplasticresin layer Cs from the recorded face along with detaching the supportBs to give a recorded material having a protective layer withoutdisarray of an image.

The protective film according to the invention is only required to beone constituted by laminating a first protective layer and a secondprotective layer made of thermoplastic resin on a support sequentially,and various modifications are possible in a range not departing from theaspect of the invention.

EXAMPLES

Hereinafter, by citing Examples of the invention and Test examplesexhibiting advantage of the invention, the invention will be explainedmore specifically, however, these Examples place no restriction on theinvention.

(Production of a Protective Film)

Protective films 1 to 23 were produced by coating respective coatingliquids (aqueous resin emulsion) for a thermoplastic resin layerincorporated with various forming materials on the whole surface ofeither side of following supports 1 to 4 uniformly in a predeterminedcoating volume by using a wire bar and drying the same to form athermoplastic resin layer. Constitution of the thermoplastic resin layerin respective protective films is listed in following Tables 1 and 2.

-   -   Support 1: PET film (“PET Lumilar S10” from PANAC, 38 μm in        thickness)    -   Support 2: OPP film having been subjected to corona discharge        treatment to a thermoplastic resin layer forming surface        (“OPU-1” from TOHCELLO CO,. LTD, 20 μm in thickness)    -   Support 3: PET film having been subjected to release treatment        (coated with silicone-based resin) to surface opposing to a        thermoplastic resin layer forming surface (“SP-PET-03-50BU” from        PANAC, 50 μm in thickness)

Support 4: PET film having been subjected to release treatment (coatedwith melamine-based resin) to surface opposing to a thermoplastic resinlayer forming surface (“PET-38SG-1” from PANAC, 38 μm in thickness)TABLE 1 Thermoplastic resin layer Pro- First protective layer Secondprotective layer tec- Film- Complex Complex tive Weight forming Weightelastic elastic film Thermoplastic average auxiliary Thick-Thermoplastic average modulus modulus Thick- No. resin Tg agent Wax nessresin Tg (40° C.) (100° C.) ness 1 Boncoat 9404   40° C. — —  5 μmBoncoat EC-819   11° C. 2.1 × 10⁷ Pa 1.9 × 10⁵ Pa 15 μm 2 ACRIT WEM-030U66.2° C. — —  5 μm Boncoat EC-819   11° C. 2.1 × 10⁷ Pa 1.9 × 10⁵ Pa 15μm core-shell type 3 ACRIT WEM-030U 66.2° C. To resin solid —  5 μmBoncoat EC-819   11° C. 2.1 × 10⁷ Pa 1.9 × 10⁵ Pa 15 μm core-shell typecontent 5 wt % 4 ACRIT WEM-030U 66.2° C. — To resin  5 μm Boncoat EC-819  11° C. 2.1 × 10⁷ Pa 1.9 × 10⁵ Pa 15 μm (core-shell solid type) content3 wt % 5 ACRIT WEM-030U 66.2° C. To resin solid To resin  5 μm BoncoatEC-819   11° C. 2.1 × 10⁷ Pa 1.9 × 10⁵ Pa 15 μm (core-shell content 5 wt% solid type) content 3 wt % 6 ACRIT WEM-030U 66.2° C. To resin solid Toresin  5 μm ACRIT WEM-202U 20.8° C. 5.3 × 10⁷ Pa 2.3 × 10⁵ Pa 15 μm(core-shell content 5 wt % solid (core-shell type) content type) 3 wt %7 ACRIT WEM-030U 66.2° C. To resin solid To resin  5 μm Boncoat 9404/  24° C. 6.1 × 10⁷ Pa 2.5 × 10⁵ Pa 15 μm (core-shell content 5 wt %solid EC-819 type) content (weight ratio 1/3) 3 wt % 8 Boncoat 9404  40° C. To resin solid To resin  5 μm ACRIT WEM-030U 66.2° C. 4.5 × 10⁸Pa 8.4 × 10⁵ Pa 15 μm content 5 wt % solid (core-shell content type) 3wt % 9 Boncoat 9404   40° C. To resin solid To resin  5 μm ACRITWEM-030U/   41° C. 3.2 × 10⁸ Pa 2.7 × 10⁵ Pa 15 μm content 5 wt % solid202U content (weight ratio 1/1) 3 wt % 10 Boncoat 9404   40° C. — — 20μm — — — — — 11 Boncoat 9404   40° C. — —  5 μm ACRIT 3042MA  105° C.7.5 × 10⁸ Pa 6.3 × 10⁶ Pa 15 μm

TABLE 2 Thermoplastic resin layer Pro- First protective layer Secondprotective layer tec- Film- Film- tive Weight In- forming Weight In-forming film Thermoplastic average organic auxiliary Thick-Thermoplastic average organic auxiliary Thick- No. resin Tg particleagent Wax ness resin Tg particle agent ness 12 Boncoat EC-819   11° C.P-73 To resin — 5 μm Boncoat EC-819   11° C. — — 15 μm 30 wt % solidcontent 5 wt % 13 Boncoat EC-819   11° C. P-78D To resin — 5 μm BoncoatEC-819   11° C. P78-D — 15 μm 30 wt % solid 5 wt % content 5 wt % 14Boncoat EC-819   11° C. ST-30 To resin — 6 μm Boncoat EC-819   11° C. —— 15 μm 5 wt % solid content 5 wt % 15 Boncoat EC-819   11° C. ST-30 Toresin To resin 5 μm ACRIT WEM- 20.8° C. — — 15 μm 30 wt % solid solidcontent 202U (core- content 3 wt % shell type) 5 wt % 16 Boncoat EC-819  11° C. ST-30 To resin — 5 μm Boncoat EC-819   11° C. — — 15 μm 70 wt %solid content 5 wt % 17 ACRIT WEM-030U 66.2° C. ST-30 To resin To resin5 μm Boncoat EC-819   11° C. — — 15 μm (core-shell 10 wt % solid solidcontent type) content 3 wt % 5 wt % 18 Movinyl 8030   17° C. — — Toresin 4 μm Movinyl 727   30° C. — To resin   5 μm solid content solidcontent 3 wt % 3 wt % 19 Movinyl 8030   17° C. ST-30 — To resin 4 μmMovinyl 727   30° C. — To resin   5 μm 10 wt % solid content solidcontent 3 wt % 3 wt % 20 Movinyl 8030   17° C. — — To resin 4 μm Movinyl870   30° C. — To resin   5 μm solid content solid content 5 wt % 3 wt %21 Movinyl 8030   17° C. — — To resin 4 μm Movinyl 727   30° C. — Toresin   5 μm solid content solid content 3 wt % 3 wt % 22 Movinyl 8030  17° C. ST-30 — To resin 4 μm Movinyl 727   30° C. — To resin   5 μm 10wt % solid content solid content 3 wt % 3 wt % 23 1) Movinyl 27.6° C.ST-30 — To resin 4 μm Movinyl 727   30° C. — To resin   5 μm 8020Movinyl 17 wt % solid content solid content 790 3 wt % 3 wt %Note 1)Constitution is such that a continuous phase is formed of Movinyl 8020,and that Movinyl 790 is dispersed in the continuous phase as a dispersedphase.Content ratio of respective resin components is Movinyl 8020: Movinyl790=3:2 (weight ratio).

Details of respective thermoplastic resins listed in Tables 1 and 2 areas follows:

-   “Boncoat 9404” an acrylic resin emulsion from DAINIPPON INK AND    CHEMICALS, INC.;-   “Boncoat EC-819” an acrylic resin emulsion from DAINIPPON INK AND    CHEMICALS, INC.;-   “ACRIT WEM-030U” an acrylic resin emulsion from Taisei Kako K.K.,    core portion Tg is 77° C., shell portion Tg is 40° C., core    portion/shell portion weight ratio=60/40;-   “ACRIT WEM-202U” an acrylic resin emulsion from Taisei Kako K.K.,    core portion Tg is 8° C., shell portion Tg is 40° C., core    portion/shell portion weight ratio=60/40;-   “ACRIT 34042MA” an acrylic resin emulsion from Taisei Kako K.K.;-   “Movynil 8030” a colloidal silica complex acrylic resin emulsion    from CLARIANT POLYMERS K.K.;-   “Movynil 727” an acrylic resin emulsion from CLARIANT POLYMERS K.K.;-   “Movynil 870” an acrylic-styrene resin emulsion from CLARIANT    POLYMERS K. K.;-   “Movynil 8020” a colloidal silica complex acrylic resin emulsion    from CLARIANT POLYMERS K.K., Tg is −22° C., MFT is less than 0° C.;-   “Movynil 790” an acrylic resin emulsion from CLARIANT POLYMERS K.K.,    Tg is 102° C., MFT is 220° C.

A film-forming auxiliary agent used for both of the first and secondprotective layers was Texanol. As for wax, a wax emulsion “SanleafCLA-3” from Sanyo Chemical Industries, LTD. was used for protectivefilms 18 to 22, and “Chemipearl WF-640” from Mitsui Chemicals was usedfor other protective films.

Details of the inorganic particles listed in Table 2 are as follows,respectively:

-   “P-73” gel-type silica from MIZUSAWA INDUSTRIAL CHEMICALS, LTD.    (trade name “MIZUKASIL”), particle diameter is 2.5 μm; “P-78D”    gel-type silica from MIZUSAWA INDUSTRIAL CHEMICALS, LTD. (trade name    “MIZUKASIL”), particle diameter is 8.0 μm; “ST-30” colloidal silica    from NISSAN CHEMICAL INDUSTRIES, LTD. (trade name “Snowtex”),    particle diameter is 16 nm.

The complex elastic modulus shown in the Table 1 is a complex elasticmodulus obtained by measuring dynamic viscoelasticity using anon-resonance forced extension vibration type DMS6100 from SEIKOINSTRUMENTS Co., Ltd. as a viscoelasticity spectrometer at temperatureof 21±2° C., humidity of 60±5%, under an atmosphere of nitrogen gasflow, at frequency of 1 Hz, at temperature rise rate of 2° C./min andminimum tension of 10 mN to form a temperature dispersion curve thereof,and selecting a value at 40° C. and 100° C. thereof. Here, whenmeasuring dynamic viscoelasticity, an emulsion of resin to be measuredwas coated on a biaxially oriented polypropylene (OPP) resin film, driedat 100° C. for 2 minutes, then left to stand overnight to form a coatingfilm of the resin on the OPP resin film, and the coating film was usedas a sample for measurement.

For the protective films 1 to 23, blocking resistance (storability)during film storage was evaluated by the following method. The result islisted in Table 3 below.

<Blocking Resistance (Storability) During Film Storage>

For each of the protective films, two A-4 size sheets were prepared. Thetwo sheets were superposed in such a manner that the thermoplastic resinlayer of one of them faced to the support of the other, which was leftto stand under the condition of a room temperature of 50° C. andrelative humidity of 0% in a state of applying load of 300 g/cm2 fromabove for 24 hours. Subsequently, the superposed two layers weredetached at a detaching angle (an angle formed between the facingthermoplastic resin layer and support) of 130 degrees and a detachingspeed of 30 cm/min to evaluate based on the following evaluationstandard by observing the state of superposed surfaces with eyes.

Evaluation Standard

A: no transfer of the thermoplastic resin layer to the support isobserved. No blocking generates even in a long term storage. Goodstorability.

B: a part of the thermoplastic resin layer has transferred to thesupport. However, no problem for practical use.

C: a bit of transfer of the thermoplastic resin layer to the support canbe distinguishable. Limit for practical use.

D: most parts of the thermoplastic resin layer have been transferred tothe support. Not effective for practical use.

(Production of a Recorded Material)

By using an ink jet printer (“MC2000” from SEIKO EPSON CORPORATION), arecorded material was produced by printing each of six colors of aqueouspigment inks including yellow, magenta, cyan, light magenta, light cyanand black to the recording face of a recording medium (“PhotographicPaper (glossy)” from SEIKO EPSON CORPORATION) by a driving amount of 3.5mg/cm2.

(Production of Heated and Pressure Bonded Material)

The protective film was superposed on the printed face of the recordedmaterial in such a way that the thermoplastic resin layer faced to theprinted face and laminated, which was subjected to a pressure bondingtreatment (line pressure of 5.0 kN/cm2, refer to following Table 3 asfor heating temperature) by allowing it to run through between a pair ofheat rolls. Thus, heated and pressure bonded material formed of therecorded material and any of the protective films 1 to 23 to givesamples for Example 1 to 22 and Comparative examples 1 to 2,respectively.

Respective samples (heated and pressure bonded material of the recordedmaterial and the protective film) for Examples 1 to 22 and Comparativeexamples 1 to 2 were evaluated for detachability according to thefollowing method. In addition, the recorded material with the protectivelayer obtained by detaching the support from the respective samples wereevaluated for appearance, scratch resistance, blocking resistance andalbum storability according to the following methods, respectively.These results are shown in Table 3 below.

<Evaluation Method of Detachability>

Only the support was detached from each of the samples (heated andpressure bonded material of the recorded material and the protectivefilm) to give a recorded material with the protective layer. Thedetaching angle (an angle formed between the support and the recordedmaterial) was 180 degrees and detaching speed was 100 cm/min. Behaviorat the detaching and the surface of the protective layer of the recordedmaterial were observed with eyes to evaluate on the basis of thefollowing evaluation standard.

Evaluation Standard

A: lift of the thermoplastic resin layer from the printed surface of therecorded material does not occur during detaching the support, resultingin no bleeding and stripping of an image. Good detachability.

B: lift of the thermoplastic resin layer from the printed surface isobserved in a part during detaching the support and bleeding orstripping of an image is slightly observed. However, no problem inpractical use.

C: lift of the thermoplastic resin layer from the printed surface isobserved in considerable parts during detaching the support and a partof the image transfers to the support. Bleeding and peeling are severe.Can not be used practically.

<Evaluation Method of Appearance>

The protective layer of the recorded material with the protective layerwas observed with eyes and determined such that a sample with clearfeeling and without interfusion of the air bubble and crack was A (goodappearance), a sample with a little meager clear feeling or a littleinterfusion of air bubbles or very small cracks was B (no problem inpractical use), and that a sample with much degraded clear feeling ordefinite observation of air bubbles or highly visible cracks was C (noteffective for practical use).

<Evaluation Method of Scratch Resistance>

The surface of the protective layer of the recorded material with theprotective layer was observed with eyes after it was slightly rubbedwith backside of the Photographic Paper <glossy> to determine such thata sample free from a scratch was A (good scratch resistance), and that asample with scratches on the surface was B (no problem in practicaluse).

<Evaluation Method of Blocking Resistance>

Two A-4 size sheets of the recorded material with the protective layerwere prepared, which were superpose such that front side of one of them(front side of the protective layer) faced to back side of the other(back side of MC Photographic Paper) and left to stand under a conditionof a room temperature of 50° C. and relative humidity of 60% in a stateof applying load of 300 g/cm2 from above for 24 hours. Subsequently, thesuperposed two sheets were detached at a detaching angle (an angleformed between the opposing protective layer and recorded material) of130 degrees and a detaching speed of 30 cm/min. Then, the state ofsuperposed faces was observed with eyes to evaluate on the basis of thefollowing evaluation standard.

Evaluation Standard

A: no transfer of the protective layer to the back side is observed.Good blocking resistance.

B: a part of the protective layer has transferred to the back side.However, no problem in practical use.

C: most parts of the protective layer have transferred to the back side.Not effective for practical use.

<Evaluation Method of Album Storability>

The recorded material with the protective layer was housed in a freealbum from KOKUYO Co., Ltd. according to an ordinary method (housed byinterleaving it between a cover film and mount), and the album was leftto stand under a circumstance of a room temperature of 60° C. and ahumidity of 60% RH for 24 hours. Subsequently, the recorded material wastaken out of the album, and condition at that time and surface of theprotective layer of the taken out recorded material were observed witheyes to evaluate on the basis of the following evaluation standard.

Evaluation Standard

A: almost no sticking between the cover film and surface of theprotective layer is observed upon taking out the recorded material fromthe album, and no change in the state of the protective layer existscompared with the state before the material was housed in the album.Good album storability.

B: a part of surface of the protective layer has stuck to the cover filmupon taking out the recorded material from the album, but it can bestripped easily and gloss change is slight compared with the statebefore the material was housed in the album. No problem in practicaluse.

C: almost whole surface of the protective layer has stuck to the coverfilm upon taking out the recorded material from album, and gloss changeis heavy compared with the state before the material was housed in thealbum. Not effective for practical use. TABLE 3 Heating temperatureRecorded material with protective film Support Protective at pressurebonding Scratch Blocking Alubam No. film No. Storability (° C.)Detachability Appearance resistance resistance storability Example 1 1 1C 40 A A B B C Example 2 1 2 C 40 A B B A A Example 3 1 3 C 40 A A B A AExample 4 1 4 C 40 A B A A A Example 5 1 5 C 40 A A A A A Example 6 1 &B 40 A A A A A Example 7 1 7 B 40 A A A A A Example 8 1 8 A 40 A B A A BExample 9 1 9 B 40 A A A A B Example 10 1 11 A 110 B B B B C Example 111 12 C 40 A B A A B Example 12 1 13 B 40 A B A A B Example 13 1 14 C 40A A B B C Example 14 1 15 B 40 A A A A B Example 15 1 16 C 40 A B B A BExample 16 1 17 C 40 A A A A A Example 17 2 18 A 100 A A A A B Example18 2 19 A 95 A A A A B Example 19 2 20 A 90 A A A A B Example 20 3 21 A100 A A A A B Example 21 4 22 A 110 A A A A B Example 22 4 23 A 100 A AA A A Comparative 1 10 B 50 C C B B C example 1 Comparative 1 1 C Noheating C C B C C example 2

Although the invention has been illustrated and described for theparticular preferred embodiments, it is apparent to a person skilled inthe art that various changes and modifications can be made on the basisof the teachings of the invention. It is apparent that such changes andmodifications are within the spirit, scope, and intention of theinvention as defined by the appended claims.

The present application is based on Japan Patent Application No.2003-415444 filed on Dec. 12, 2003, the contents of which areincorporated herein for reference.

1. A protecting film for covering a recording face of a recordingmedium, an image being formed on the recording face by a thermaltransfer type overcoat process, the protecting film comprising: asupport; a first protective layer, formed of thermoplastic resin, andformed on the support; and a second protective layer, formed ofthermoplastic resin, and formed on the first protective layer.
 2. Theprotecting film according to claim 1, wherein the thermoplastic resinforming the first protective layer has a glass transition temperaturehigher than that of the thermoplastic resin forming the secondprotective layer.
 3. The protecting film according to claim 2, wherein adifference between the glass transition temperature of the thermoplasticresin forming the first protective layer and the glass transitiontemperature of the thermoplastic resin forming the second protectivelayer is from 10 to 100° C.
 4. The protecting film according to claim 2,wherein the glass transition temperature of the thermoplastic resinforming the first protective layer is from 30 to 130° C.
 5. Theprotecting film according to claim 1, wherein the first protective layerincludes an inorganic particle.
 6. The protecting film according toclaim 5, wherein a content of the inorganic particle is from 10 to 60%by weight relative to resin solid content.
 7. The protecting filmaccording to claim 5, wherein the inorganic particle is colloidalsilica.
 8. The protecting film according to claim 5, wherein the firstprotective layer includes a continuous phase formed of thermoplasticresin and a dispersed phase formed of thermoplastic resin dispersed inthe continuous phase; and wherein the continuous phase contains theinorganic particle.
 9. The protecting film according to claim 1, whereina complex elastic modulus of the thermoplastic resin forming the secondprotective layer is 4.0×10⁸ Pa or more at 40° C. in a temperaturedispersion curve of dynamic viscoelasticity that is measured atfrequency of 1 Hz, temperature rise rate of 2° C./min and minimumtension of 10 mN.
 10. The protecting film according to claim 1, whereina complex elastic modulus of the thermoplastic resin forming the secondprotective layer is 2.5×10⁵ Pa or less at 100° C. in a temperaturedispersion curve of dynamic viscoelasticity that is measured atfrequency of 1 Hz, temperature rise rate of 2° C./min and minimumtension of 10 mN.
 11. The protecting film according to claim 2, whereinthe glass transition temperature of the thermoplastic resin forming thesecond protective layer is from −20 to 60° C.
 12. The protecting filmaccording to claim 5, wherein the glass transition temperature of thethermoplastic resin forming the second protective layer is from −20 to60° C.
 13. The protecting film according to claim 9, wherein the glasstransition temperature of the thermoplastic resin forming the secondprotective layer is from −20 to 60° C.
 14. The protecting film accordingto claim 10, wherein the glass transition temperature of thethermoplastic resin forming the second protective layer is from −20 to60° C.
 15. The protecting film according to claim 1, wherein the firstprotective layer includes wax.
 16. A method for producing a recordedmaterial by using a protecting film according to claim 1, comprising thesteps of: forming an image on a recording face of a recording medium;laminating the recording medium on which the image is formed and theprotecting film so that the recording face is superposed on the secondprotective layer of the protecting film; applying heat and pressure tothe laminated recording medium and protecting film so as to bond therecording medium and protecting film each other, wherein heatingtemperature at the heating and pressure bonding is equal to or greaterthan the glass transition temperature of the thermoplastic resin formingthe second protective layer.
 17. The method according to claim 16,wherein the image is formed by an ink jet system.
 18. A recordedmaterial produced by the method for producing the recorded materialaccording to claim 16.